Photophysical properties of porphyrins with sterically distorted and partially screened macrocycles

Ivashin, N. V.; Shchupak, E. E.; Panarin, A. Yu.; Sagun, E. I.

doi:10.1134/s0030400x15060107

Cited by 4 publications

(3 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, it should also be noted that porphyrins, and related molecules, show a reduced excited state lifetime when their geometry is strongly distorted. This reducing effect has been noted in both free and metal-containing porphyrins and on both singlet and triplet excited states (27)(28)(29)(30)(31).…”

Section: Significancementioning

confidence: 83%

Macrocycle ring deformation as the secondary design principle for light-harvesting complexes

Vico

Anda

Osipov

et al. 2018

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Natural light-harvesting is performed by pigment-protein complexes, which collect and funnel the solar energy at the start of photosynthesis. The identity and arrangement of pigments largely define the absorption spectrum of the antenna complex, which is further regulated by a palette of structural factors. Small alterations are induced by pigment-protein interactions. In light-harvesting systems 2 and 3 from , the pigments are arranged identically, yet the former has an absorption peak at 850 nm that is blue-shifted to 820 nm in the latter. While the shift has previously been attributed to the removal of hydrogen bonds, which brings changes in the acetyl moiety of the bacteriochlorophyll, recent work has shown that other mechanisms are also present. Using computational and modeling tools on the corresponding crystal structures, we reach a different conclusion: The most critical factor for the shift is the curvature of the macrocycle ring. The bending of the planar part of the pigment is identified as the second-most important design principle for the function of pigment-protein complexes-a finding that can inspire the design of novel artificial systems.

show abstract

Section: Significancementioning

confidence: 83%

Macrocycle ring deformation as the secondary design principle for light-harvesting complexes

Vico

Anda

Osipov

et al. 2018

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…In addition to these factors, there are literature reports asserting that distortion of the macrocycle also enhances nonradiative relaxation. The photophysical consequences of nonplanar distortions are reported for porphyrins, − but are much less well understood in Pcs. ,, Distorted or nonplanar Pcs have been reported, but the accompanying photophysical studies focus on the electronic and emission spectra. − ,, Conversely, detailed photophysical studies of Pcs often neglect considering the possibility of structural distortions . In porphyrins, distortion is known to cause broadened, red-shifted absorption and emission bands, increased Stokes shifts, lower fluorescence quantum yields and lifetimes, and even higher rates of intersystem crossing. − All of these characteristics were unexpectedly observed in our series of Pcs, lending credibility to the hypothesis that the more highly substituted members adopt nonplanar conformations.…”

Section: Results and Discussionmentioning

confidence: 99%

Tuning the Structure and Photophysics of a Fluorous Phthalocyanine Platform

et al. 2016

View full text Add to dashboard Cite

Phthalocyanines are an important class of industrial dyes with potential commercial applications ranging from photovoltaics to biomedical imaging and therapeutics. We previously demonstrated the versatility of the commercially available zinc(II) hexadecafluorophthalocyanine (ZnF16Pc) as a platform for rapidly developing functional materials for these applications and more. Because this core-platform approach to dye development is increasingly common, it is important to understand the photophysical and structural consequences of the substitution chemistry involved. We present a fundamental study of a series of ZnF16Pc derivatives in which the aromatic fluorine atoms are progressively substituted with thioalkanes. Clear spectroscopic trends are observed as the substituents change from electron-withdrawing to electron-releasing groups. Additionally, there is evidence for significant structural distortion of the normally planar heterocycle, with important ramifications for the photophysics. These results are also correlated to DFT calculations, which show that the orbital energies and symmetries are both important factors for explaining the excited-state dynamics.

show abstract

“…Проведенное нами ранее квантово-химическое моде-лирование комплексов молекулярного кислорода в ос-новном состоянии с порфиринами указывает на слабость межмолекулярного взаимодействия в этом случае [26]. Вместе с тем экспериментальные данные [27] указывают на то, что излучательная константа скорости перехода a 1 g − X 3 − g немного больше таковой в поглощении.…”

Section: Introductionunclassified

Квантово-Химическое Моделирование Влияния Растворителя На Спонтанное Излучение Синглетного Кислорода

Ivashin

Shchupak

2018

Журнал Технической Физики

View full text Add to dashboard Cite

Поступила в редакцию 09.02.2017 г. В окончательной редакции 09.08.2017 г. Проведено молекулярное моделирование влияния растворителя на излучательную константу скорости kr синглетного кислорода. Данное исследование включало поиск наиболее вероятных конформаций комплексов молекул синглетного кислорода и 10 растворителей и расчет для них дипольных моментов M переходов aПоказано, что усреднение M a-b по конформациям с учетом вероятности их образования для комплексов, не содержащих атомы с большим атомным номером (Cl, S), позволяет получить значения, которые, как правило, хорошо коррелируют с поведением kr на эксперименте. Учет возможности уменьшения расстояния (по сравнению с равновесным) между молекулами в столкновительном комплексе при комнатной температуре позволил добиться удовлетворительного соответствия расчетных и экспериментальных данных также для комплексов с ССl 4 , C 2 Cl 4 и CS 2 . Полученные данные свидетельствуют о том, что на kr оказывает влияние целый ряд факторов. Имеющая место в ряде случаев корреляция kr с молекулярной поляризуемостью связана, с одной стороны, с ее влиянием на силу дисперсионных взаимодействий в комплексе, с другой -с тем, что она в определенной мере отражает положение верхних заполненных орбиталей молекулы растворителя. Оба фактора оказывают влияние на степень смешивания π-орбиталей молекулы синглетного кислорода с орбиталями молекулы растворителя, которое, как было установлено ранее, способствует активации перехода a

show abstract

Photophysical properties of porphyrins with sterically distorted and partially screened macrocycles

Cited by 4 publications

References 25 publications

Macrocycle ring deformation as the secondary design principle for light-harvesting complexes

Macrocycle ring deformation as the secondary design principle for light-harvesting complexes

Tuning the Structure and Photophysics of a Fluorous Phthalocyanine Platform

Квантово-Химическое Моделирование Влияния Растворителя На Спонтанное Излучение Синглетного Кислорода

Contact Info

Product

Resources

About